Year Measure 1996 5.57 1997 5.08 1998 4.6 1999 4.2 2000 4.1 2001 4.1 2002 4 2003 3.6 2004 3.5 2005 3.4 2006 3.7 2007 4.2 2008 4.6 2009 5 2010 5.3 2011 5.48242